Optimizing Combinations of Flavonoids Deriving from Astragali Radix in Activating the Regulatory Element of Erythropoietin by a Feedback System Control Scheme
Figure 2
The AR extract and flavonoids stimulated the HRE-mediated transcriptional activity in cultured HEK293T cells. (a) Six repeats of hypoxia responsive elements (HRE: 5′-TCG AGG CCC TAC GTG CTG TCT CAC ACA GCC TGT CTG ACG-3′) were subcloned in an expression vector of luciferase named as pHRE-Luc (upper panel). Cultured HEK293T cells, transfected with pHRE- Luc, were treated with CoCl2 (50 mM) or mineral oil layering for 0 to 48 hours. The cell lysates were subjected to luciferase assay to measure the transcriptional activity driven by HRE (lower panel). (b and c) The pHRE-Luc-transfected HEK293T cells were treated with AR extracts (b) and flavonoids (c) for 48 hours to determine the promoter-driven luciferase (pHRE-Luc) activity. Values are expressed as the percentage of increase to basal reading (untreated culture) and in mean ± SD, where , each with triplicate samples.
